The present invention generally relates to a storage system and a data management method, and, for instance, can be suitably applied to a storage system that performs a full backup or a backup using a snapshot.
This storage system manages data using a logical volume (hereinafter referred to as a “logical volume”) formed in a storage extent provided by a hard disk drive.
As a method of managing data, there is a method of periodically executing a full backup of a volume in which a user reads and writes data in a cycle of, for instance, every day or every week. As another method of managing data, there is a method of using a snapshot function loaded in a storage apparatus and periodically creating a snapshot formed from a data image of a volume at a certain point in time in a cycle of, for instance, every 12 hours or every day.
The backup data obtained by performing a full backup and the differential data obtained by using a snapshot are obtained through different methods. As a result of separately using the backup data and the differential data obtained through different methods, the volume or data stored in such volume can be restored.
Japanese Patent Laid-Open Publication No. H7-84728 discloses a data management method using technology of performing a full backup and technology of performing backup using differential data. This document proposes a data management method of deciding in a storage system of whether to perform a full backup by comparing a predetermined threshold value and the amount of differential, or perform backup using differential data.